fs/fuse: fix ioctl type confusion
fuse_dev_ioctl() performed fuse_get_dev() on a user-supplied fd,
leading to a type confusion issue. Fix it by checking file->f_op.
Signed-off-by: Jann Horn <jann@thejh.net>
Acked-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 80cc1b3..ebb5e37 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -2246,7 +2246,15 @@
err = -EINVAL;
if (old) {
- struct fuse_dev *fud = fuse_get_dev(old);
+ struct fuse_dev *fud = NULL;
+
+ /*
+ * Check against file->f_op because CUSE
+ * uses the same ioctl handler.
+ */
+ if (old->f_op == file->f_op &&
+ old->f_cred->user_ns == file->f_cred->user_ns)
+ fud = fuse_get_dev(old);
if (fud) {
mutex_lock(&fuse_mutex);